The present invention concerns logging carriages of the type supported for travel along an elevated cable for the conveyance of felled logs to a log unloading site.
The term carriage in the logging industry denotes generally an elevated car from which a drop line is suspended for securement about a log or logs with the car being powered along its supporting cable to a log unloading site by an in-haul drum equipped yarder. The carriage may be outwardly positioned along the elevated cable by gravity or by the drum controlled line reversed through a remote sheave. Commonly carriages also include ratio controlled clamping mechanisms momentarily securing the carriage in place to its supporting cable while the drop line is being retrieved to the carriage with attached log or logs, termed side haul pulling. The prior art includes carriages having sizable internal combustion engines therein for the paying out and retrieving of the drop line carried by engine driven, carriage mounted drum. A variation of this latter arrangement is found in U.S. Pat. No. 3,083,839 wherein a carriage mounted engine serves simply to pay out or "throw slack" in the drop line with subsequent retrieval of the loaded drop line being accomplished by means of a powered yarder drum thereby permitting a carriage engine of lower horsepower with a weight reduction in the carriage and hence an increased "payload" over the first mentioned carriages. Also utilized in carriages is a radio controlled brake to hold the drop line and its load in fixed relationship to the carriage during yarding of the carriage and load to the log discharge site.